Apparatus for reading optically encoded soundtracks
AssigneeNational Film Board of Canada
InventorsMichael W. Paul, Sydney T. Wiles
Life of this patent
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Abstract
An apparatus for reading variable area optically encoded soundtracks has a light source, a lens system and a detector. The detector can be a linear array, for example a CCD array, with an integral slit, with the lens system imaging the soundtrack in the plane of the slit. The apparatus includes circuitry for processing the detector output signal. The processing circuitry can be provided with a feedback control circuit to condition the detector output signal so that the resulting audio signal is not affected by variations in the film or electronic components. Further, a circuit can be included for detecting whether an analogue or digital soundtrack is present, and automatically switching the output of an amplification circuit between analogue and digital outputs.
Claims41
An apparatus, for reading an audio signal track, incorporated as an optically encoded variable area track on a tape, said apparatus comprising:
- a light source for illuminating a soundtrack on the tape from one side thereof;
- a linear detector array, for location on the other side of the soundtrack and including an integral slit which determines a transverse strip of the image of the soundtrack that is read;
- and said linear detector array including means for producing an encoded signal in response to the image of the soundtrack.
An apparatus, for reading a variable area soundtrack, incorporated as an optically encoded variable area track, on a tape, said apparatus comprising:
- a light source for illuminating one side of the soundtrack;
- detector means for location on the other side of the soundtrack;
- said detector means including integral slit means for causing a narrow, transverse strip of the soundtrack to be detected by said detector means, and said detector means producing an encoded signal indicative of the detected transverse strip of the soundtrack;
- processing means, coupled to said detector means, for processing said encoded signal into an output audio signal;
- and said processing means including feedback control means for conditioning said encoded signal so that said output audio signal is substantially uniform and independent of the characteristics of said variable area soundtrack.
An apparatus for reading a variable area soundtrack, incorporated as an optically encoded variable area track, on a tape, said apparatus comprising:
- a light source for illuminating one side of the soundtrack;
- detector means for location on the other side of the soundtrack, and having a encoded signal output;
- processing means connected to said encoded signal output of the detector, and said processing means having a processed signal output;
- a digital-analogue control unit connected to the output of said processing means and having an analogue input, a digital input, a control input, and an audio signal output;
- and control means for detecting whether an analogue or digital soundtrack is present and generating a decode control output, said control means being connected to said control input of said digital-analogue control unit.
Dependencies are inferred from the claim text.